The use of linerless labels is becoming widespread due to relatively low cost of such labels and due to their relative environmental friendliness. A number of different dispensers has been developed--such as shown in the above-mentioned U.S. patent application, U.S. Pat. Nos. 5,375,752 and 5,417,783, European published application 0577241, and co-pending U.S. application Ser. No. 08/312,068 filed Sep. 26, 1994--to facilitate dispensing of such labels. Each of those dispensers is particularly suited for certain dispensing requirements and can successfully dispense linerless labels without prohibitive difficulties. However, there are some circumstances for which such dispensers are not ideally suited, and therefore the linerless label dispenser according to the above-mentioned U.S. patent application--and its associated cutting mechanism--have been developed.
The linerless label dispenser, and its associated cutting mechanism, according to the invention disclosed in the above-identified patent application are ideally suited for dispensing linerless labels from a roll even when the labels are not perforated on the roll. The dispenser can automatically print the labels just prior to dispensing, and dispenses them in a manner that substantially avoids jamming of the printer or the cutting mechanism.
According to one aspect of that invention a linerless label dispenser is provided comprising the following components: A support for a supply of continuous form linerless labels, each label having a pressure sensitive adhesive face and an adhesive-release material coated face. An adhesive-release material guide structure for engaging the adhesive face of labels from the supply of labels. A print head, on the opposite side of the guide structure from the supply of labels, for printing the release material coated face of labels from the supply of labels. A stripper surface, on the opposite side of the print head from the release material structure, the stripper surface of adhesive-release material. A stationary anvil blade, on the opposite side of the stripper surface from the print head, for engaging the adhesive face of labels from the supply of labels. And an automatic rotary cutter cooperating with the stationary anvil blade for engaging the release material coated face of labels from the supply of labels, and cutting individual labels to be dispensed from the supply of continuous form of linerless labels.
The support for the continuous form linerless labels of that invention comprised a conventional shaft mounting a hub about 25% of the length of the core of a roll of linerless labels mounted on the hub. The linerless labels may either be perforated, or may have marks applied thereto indicating the approximate position at which the web of labels from the roll are to be severed into individual labels.
The adhesive-release material guide structure is mounted adjacent a plastic guide which engages the release material face of the labels, and preferably the adhesive-release material thereof is a plasma coating such as disclosed in U.S. Pat. No. 5,375,752, the disclosure of which is hereby incorporated by reference herein.
After the guide structure, the labels typically pass under a sensor which either senses the perforations or marks indicating the division between labels, which cooperates with a control mechanism for the printer and subsequent rotary cutter. The print head may be of any conventional type that is capable of printing on the release material, preferably a non-impact printer such as an ink jet printer. Where a thermosensitive coating is also provided for the labels, the print head may be a thermal print head or a thermal transfer print head. Typically the print head cooperates with a print roller, which may be plasma coated, but preferably is a silicone roller.
Just downstream of the print head is a support which supports the stripper surface and the stationary anvil blade. The adhesive-release material of the stripper surface preferably also is a plasma coating, and the stripper surface is disposed at an upwardly directed (from the print head) angle of between about 20-35.degree. (preferably about 27.degree.) with respect to the horizontal so that the labels printed by the print head move upwardly at an angle from the print head to the rotary cutter. The provision of such an angle has been found to minimize jams of the printer and the cutter. A stripper surface also may have a plurality of upwardly extending extensions formed on at least a part thereof (e.g. a portion of between 5-20% of the width of a linerless label passing thereover) for decreasing the surface tension thereof.
The stationary anvil blade is preferably also coated with a release material such as plasma coatings or textured paint and is immediately adjacent the stripper surface. It has been found according to the present invention that jamming of the printer and rotary cutter are minimized if the anvil blade projects upwardly from a support surface and downwardly spaced for a stripper surface a sufficient distance to insure that the leading edge of the label (the edge being cut) is not smashed. It has been found that being set slightly below the stripper surface in a range between about 0.001-0.008 inches (preferably about 0.002-0.004 inches) is most effective.
The rotary cutter may comprise a conventional off the shelf structure, except for the release coated rotary blade, such as a Hitachi rotary cutter Model #V15A. The release coat may be plasma coatings or textured paint.
Under some circumstances it is desirable to have an exit roller downstream of the rotary cutoff mechanism to facilitate dispensing of the cut labels, such as through an exit opening in a housing. Such an exit roller, when provided, also preferably has a release coated surface, and that surface is also preferably grooved (between about 5-20% of the width of a linerless label engaged thereby) and typically cooperates with a hold down mechanism of any conventional type.
While the dispenser as described in prior application Ser. No. 08/544,132 is considered eminently suitable for its purposes, it has been found that many thermal and other non-impact printers are typically placed on their side due to space constraints or cabinet constructions rather than on their base or vertical axis. Wiper elements are conventionally used to prevent the accumulation of adhesive on the rotary cutting blade. Such wiper elements are typically formed of felt or other cloth material which have a tendency to allow the silicone oil necessary to clean the blade to migrate toward the side of the blade which is face down. That is, the silicone oil migrates toward one end of the wiper due to the forces of gravity. Consequently, an unacceptable situation arises as only part of the blade is being coated with silicone oil while adhesive is allowed to build up on another part of the blade. This requires cleaning or replacement of the blade, as well as replacement or refilling of the wiper element.
According to the present invention, it has been discovered that an open-celled foam wiper or sponge retains the silicone oil substantially across the entirety of its surface such that the silicone oil is applied to the entire surface of the blade notwithstanding an orientation of the rotary cutter and wiper other than horizontally as intended. It is believed that the enhanced wicking action of the foam material maintains the silicone oil along the entire surface of the wiper element whether it extends horizontally or vertically. Thus, the open-celled foam material is the material of choice for the wiper element due to its superior wicking ability.
A further difficulty with linerless label dispensers resides in the tendency of exit rollers of printers to continue to drive the label after the label has been severed from the web by a cutter. If there is insufficient area for the label to rest at the exit port of the housing, then the label can simply fall out of the printer requiring the user to pick the label up off the floor. If the adhesive side falls face down, the label is lost and the user has to print a second label and take the time to remove the label from the floor. Also, the label may catch itself on the exterior of the housing and then swing into contact with the housing itself. This causes the label to stick to the outside of the housing and repeated instances can cause blockage of the exit port of the housing.
In accordance with the present invention and to alleviate that problem, the exit port of the printer housing is provided with a plate which not only provides a surface area for the label to rest until needed but also serves to lift the label slightly from the guide path of the labels egressing from the printer to avoid the problem of the label getting caught and swinging down into contact with the housing. The upward angle of the plate extends within a range of 5.degree. to about 25.degree. relative to the guide path and an optimum angle is about 10-20.degree.. Thus, an obtuse angle of approximately 155.degree. to 175.degree. with a preferred obtuse angle of 160-170.degree. is provided relative to the path of movement of the label exiting the housing. The plate may extend from the housing about 1/2 inch but longer or shorter lengths of plates can be used depending upon the length of the label. The plate can either be coated with a plasma coating or, more preferably, with a textured paint which prevents the label from sticking to the surface. Because the plate is not an active transport surface for the label material, a textured paint rather than a plasma coating is preferred. The textured paint affords a release surface but not as great a release surface as that provided by a plasma coating. Thus, the label can beneficially cling to the plate having the textured paint coating yet can be easily removed when needed. If the printer is orientated on its side, the label is ejected from the printer and grasps the plate so that it is still substantially perpendicular to the floor thus facilitating grasping of the label.
In another aspect of the present invention, feeding linered base material through a printer from a supply has not caused problems for the supply to track through the printer because the stock simply unwinds itself due to the low coefficient of friction created by the release liner. Thus, the label supply would not wobble nor would the label stock skew when entering the printing section of the printer. Many conventional label printers are provided with a shaft on which a small hub is provided to accommodate the label material. The size of the hub did not matter with the liner-based stock as there was no additional forces applied to the stock. Thus, a very small hub, having a contacting area approximately 25% of the contact area of the core of the supply of linered stock, was typically provided. However, this standard hub did not operate satisfactorily in a linerless environment.
Linerless labels, due to the absence of the release layer, have a substantially increased peeling force to remove the label material from the next layer of labels due to the pressure sensitive adhesive face on the supply. This creates an additional force which causes tracking problems within the printer. Thus, the linerless label material would sometimes be skewed when it entered the printhead or may contact coated face of linerless labels and cutting the labels and a plate carried by the housing and extending outwardly of the exit opening, the plate being angled to form an obtuse angle with the predetermined path and lying along the pressure sensitive adhesive face of the linerless label passing through the exit opening.
In a further preferred embodiment according to the present invention, there is provided a cutting mechanism for linerless labels each having a pressure sensitive adhesive face and an adhesive-release material coated face, the mechanism comprising a stripper surface of adhesive-release material for engaging the adhesive face of linerless labels, an anvil blade adjacent the stripper surface for engaging one of the adhesive face and release material coated face of linerless labels, a rotary cutter cooperating with the blade for engaging another of the adhesive face and the release material coated face of linerless labels and cutting the labels and a wiper impregnated with silicone oil for wiping the rotary cutter to prevent build up of adhesive on the rotary cutter, the wiper being formed of an open-cell foam material.
In a still further preferred embodiment according to the present invention, there is provided a linerless label dispenser comprising a support for a supply of continuous form linerless labels wound on a core, each label having a pressure sensitive adhesive face and an adhesive-release material coated face, the support including a hub mounted for rotation and having a contact area with the core in excess of 50% of the area of the core of the supply of linerless labels, a guide structure for engaging the labels from the supply of labels, a printhead, on the opposite side of the guide structure from the supply of labels, for surfaces beyond the active transport surfaces which are not protected with release coatings so that the label material may stick to the unprotected portions of the dispenser.
In accordance with the present invention, an adapter hub is provided on the shaft so that the contact area between the adapter hub and the conventional machine hub with the inside diameter of the core of the linerless label supply is in excess of 50% of the area of the core of the label supply. Thus, by adding an additional hub, the problem of skewing and tracking of the supply label through the dispenser and printer can be eliminated. The area covered by the hub can be as high as 100% of the area of the core but a hub combination which covers up to about 75% of the surface area works well. Additionally, because of the different sizes of the labels, an adapter hub which increases the contact area to 75%, for example, for a 4 inch wide label web, may fit a 3 inch wide label led affording 100% contact area. Consequently, a single adapter hub may serve a number of different sizes of cores.
In a preferred embodiment according to the present invention, there is provided a dispensing mechanism for linerless labels each having a pressure sensitive adhesive face and an adhesive-release material coated face, the mechanism comprising a housing defining a guide path for linerless labels including a stripper surface of adhesive-release material for engaging the adhesive face of linerless labels and an exit opening for supplying linerless labels from the mechanism along a predetermined path, an anvil blade adjacent the stripper surface for engaging the adhesive face of linerless labels, a cutter cooperating with the anvil blade for engaging the release material printing the release material coated face of the labels from the supply of labels, a stripper surface on the opposite side of the printhead from the release material structure, and formed of adhesive-release material, an anvil blade, on the opposite side of the stripper surface from the printhead, for engaging one of the adhesive release material coated face and the pressure sensitive adhesive face of labels from the supply of labels and a rotatory cutter cooperating with the anvil blade for engaging another of the adhesive-release material coated face and the pressure sensitive adhesive face of labels from the supply of labels, and cutting individual labels to be dispensed from the supply of continuous form of linerless labels.
It is a primary object of the present invention to provide an effective linerless label dispenser and a cutting mechanism for use therewith. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.